Indexable cutting insert

Abstract

The proposed technology relates to an indexable cutting insert (10) for a cutting tool. The cutting insert (10) comprises: a first side surface (12) and an opposing second side surface (14), and a peripheral surface (16) extending between the first side surface (12) and the second side surface (14). The cutting portion (18) comprises a first cutting face (24) and an opposing second cutting face (26), a flank face (28) extending between the first cutting face (24) and the second cutting face (26), a first cutting edge (20) between the first cutting face (24) and the flank face (28), and a second cutting edge (22) between the second cutting face (26) and the flank face (28). The cutting portion (18) is bisected by a first plane (AA′) transverse to the first side surface (12) and the cutting portion (18) has a biconcave cross-section transverse to the first plane (AA′).

1 - 17 . (canceled) 
     
     
         18 . An indexable cutting insert for a cutting tool, comprising:
 a first side surface, an opposing second side surface, and a peripheral surface extending between the first side surface and the second side surface; and   a cutting portion comprising a first cutting face, an opposing second cutting face, a flank face extending between the first cutting face and the second cutting face, a first cutting edge between the first cutting face and the flank face, and a second cutting edge between the second cutting face and the flank face;   wherein the cutting portion is bisected by a first plane transverse to the first side surface; and   wherein the cutting portion has a cross-section transverse to the first plane that is concave on both the first side surface and on the second side surface.   
     
     
         19 . The cutting insert according to  claim 18 , wherein, on the cutting portion, the first side surface is concave and defines a portion of a surface of a first elliptical cylinder having a first cylinder axis in the first plane; and
 wherein, on the cutting portion, the second side surface is concave and defines a portion of a surface of a second elliptical cylinder having a second cylinder axis in the first plane.   
     
     
         20 . The cutting insert according to  claim 19 , wherein the first cylinder axis and the second cylinder axis diverge in the direction of the flank face. 
     
     
         21 . The cutting insert according to  claim 19 , wherein each of the first cylinder and the second cylinder has a transverse cross-section that forms an ellipse, wherein the transverse cross-section has a semi-major axis that is transverse to the first plane. 
     
     
         22 . The cutting insert according to  claim 18 , wherein the cutting portion has a width between the first side surface and the second side surface that increases towards the flank face. 
     
     
         23 . The cutting insert according to  claim 18 , wherein the cutting portion is bisected by a second plane transverse to the first plane and centered between and extending in the same directions as the first side surface and the second side surface, and wherein the cutting portion has a radial side clearance angle in the range 1° to 2.5° between the second plane and a line tangential to the first side surface at the first cutting edge and at the second cutting edge and in a plane parallel to the first plane. 
     
     
         24 . The cutting insert according to  claim 23 , wherein the cutting portion has a tangential side clearance angle in the range 2.5° to 10° between the second plane and a line tangential to the first side surface at one of the first cutting edge and the second cutting edge, and in a plane perpendicular to the first plane and the second plane. 
     
     
         25 . The cutting insert ( 10 ) according to  claim 18 , wherein the first cutting face has a first rake portion at the first cutting edge, and the second cutting face has a second rake portion at the second cutting edge, wherein the first rake portion and the second rake portion curve inward with respect to the cutting portion. 
     
     
         26 . The cutting insert according to  claim 18 , wherein the cutting insert has a base portion, the cutting portion has a proximal end and a distal end, the cutting portion is attached to the base portion at the proximal end of the cutting portion, the first cutting edge and the second cutting edge are located at the distal end of the cutting portion, and the base portion has a rounded profile at the proximal end of the base portion. 
     
     
         27 . The cutting insert according to  claim 26 , wherein the base portion has a through-going hole between the first side surface and the second side surface. 
     
     
         28 . The cutting insert according to  claim 26 , wherein the base portion has a portion shaped as a sector of a ring with a sector angle in the range 60° to 180°. 
     
     
         29 . The cutting insert according to  claim 28 , wherein the portion shaped as a sector of a ring has a uniform radial thickness. 
     
     
         30 . The cutting insert according to  claim 26 , wherein the cutting insert has a thickness transverse to the first plane first plane that increases when going from the proximal end of the base portion to the distal end of the cutting portion. 
     
     
         31 . The cutting insert according to  claim 18 , wherein the cutting insert constitutes a unitary body. 
     
     
         32 . The cutting insert according to  claim 18 , wherein the cutting insert is of sintered or cemented carbide. 
     
     
         33 . A cutting tool assembly for machining a work part rotating on a rotational axis, comprising:
 a cutting tool; and   an indexable cutting insert supported by the cutting tool, the indexable cutting insert comprising:   a first side surface, an opposing second side surface, and a peripheral surface extending between the first side surface and the second side surface; and   a cutting portion comprising a first cutting face, an opposing second cutting face, a flank face extending between the first cutting face and the second cutting face, a first cutting edge between the first cutting face and the flank face, and a second cutting edge between the second cutting face and the flank face;   wherein the cutting portion is bisected by a first plane transverse to the first side surface; and   wherein the cutting portion has a cross-section transverse to the first plane that is concave on both the first side surface and on the second side surface;   wherein the cutting tool is further configured to support the indexable cutting insert so as to orient the indexable cutting insert with the first plane transverse to the rotational axis.   
     
     
         34 . A method for machining a work part rotating on a rotational axis, the method comprising the steps of:
 (a) providing an indexable cutting insert, comprising:   a first side surface, an opposing second side surface, and a peripheral surface extending between the first side surface and the second side surface; and   a cutting portion comprising a first cutting face, an opposing second cutting face, a flank face extending between the first cutting face and the second cutting face, a first cutting edge between the first cutting face and the flank face, and a second cutting edge between the second cutting face and the flank face;   wherein the cutting portion is bisected by a first plane transverse to the first side surface; and   wherein the cutting portion has a cross-section transverse to the first plane that is concave on both the first side surface and on the second side surface; and   (b) supporting the indexable cutting insert in a cutting tool so that the indexable cutting insert is oriented with the first plane transverse to the rotational axis of the rotating work part.